The surface modification of fluoroelastomer by using different fluorination duration was investigated.The results of X-ray photoelectron spectroscopy (XPS) showed that a greater number of fluorine-containing chemical groups,such as-CF3,-CF2 and-CF,were bonded on the fluoroelastomer surface in the form of covalent bond.With the increase of the fluorination duration,the contents of fluorine-containing chemical groups were dramatically increased and then unchanged gradually.Scanning electronic microscopy (SEM) revealed that impurities and lengthwise furrows on the fluoroelastomer surface were gradually disappeared with increase of the fluorination duration,and finally the fluoroelastomer surface became clear and smooth.The surface energy test showed that,by the combination of chemical structures and physical morphologies of the fluoroelastomer surface,the polar component and the dispersive component of surface energy were decreased with increase of reaction duration.The tensile strength was slightly increased and the elongation was slightly decreased after fluorination becauese of the cross-linking reaction by fluorination.At the same time,the friction coefficient of fluoroelastomer decreased remarkably from 1.18 to about 0.50 with increase of the fluorination duration.%采用F2/N2混合气体对F246型氟弹性体进行表面直接氟化改性.X-射线光电子能谱(XPS)测试结果表明,直接氟化后,在氟弹性体表面以共价键的形式引入了大量的-CF3、-CF2和CF等含氟基团,随着氟化时间的增加,氟弹性体表面的含氟基团先增加,然后逐渐趋于稳定.扫描电镜(SEM)结果表明,随着氟化反应时间的延长,氟弹性体表面的杂质和沟壑结构逐渐消失,最终形成了较为平整的表面形貌.同时表面能测试结果表明,随着氟化时间的增加,在氟弹性体表面化学结构和物理结构的共同作用下,氟弹性体表面能极性分量和色散分量逐渐降低.由于氟化过程会引起橡胶表面交联反应,因此氟化处理后的氟弹性体的拉伸强度略微增加,断裂伸长率略微降低.同时,随着氟化时间的增加,氟弹性体的摩擦因数明显下降,从1.18下降到0.50左右.
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